The ppt describes in detail about coagulation and clotting factors and related medical conditions.

1. Presented by
Dr Dinsha K N
1st year MDS

2.  Introduction
 Events in hemostasis
 Clotting factors
 Coagulation pathways
 Intravascular anticoagulants
 Applied aspects
 Conclusion
 References

3.  ‘’The ability of the body to control the flow of
blood following vascular injury . The process
of blood clotting and then the subsequent
dissolution of the clot, following repair of the
injured tissue, is termed hemostasis’’.

4.  BLEEDING TIME : Time interval between the skin
puncture and spontaneous ,un assisted stoppage
of bleeding (2-9min)
 CLOTTING TIME : Time interval between skin
puncture and formation of fibrin threads(3-6min)
 PROTHROMBIN TIME :Time required for the
coagulation to take place(12sec) .It represents the
time needed for plasma to clot .Measures
effectiveness of extrinsic pathway
 PARTIAL THROMBOPLASTIN TIME :Measures
the effectiveness of intrinsic pathway (25-40sec)

7.  Primary and secondary hemostasis
 Primary hemostasis: Integrity of vascular wall
and adequacy of platelets are essential .
 Secondary hemostasis: Proper fibrin clot
formation .

8. (1) Vascular constriction
(2) Formation of a platelet plug
(3) Formation of a blood clot as a result of blood
coagulation
(4) Eventual growth of fibrous tissue into the blood
clot .

9. VASCULAR CONSTRICTION :
 Trauma to the vessel wall causes contraction of
the smooth muscles , thus reduces the flow of the
blood from ruptured vessel
 Local myogenic spasm
 Local autacoid factors
 Nervous reflexes
 For smaller vessels much of the vasoconstriction is
done by platelets by releasing thromboxaneA

11. PLATELET PLUG FORMATION
 Small vascular rupture often sealed by platelet plugs rather
than by a blood clot.
PLATELETS :
 Also known as thrombocytes
 Minute discs with 1-4 microns diameter
 Formed in bone marrow from megakaryocytes, extremely
large cells in hematopoietic series in marrow
 No nuclei and cannot divide
 Cytoplasm contains actin and myosin filaments and
thrombosthenin
 Mitochondria and enzyme systems capable of producing ATP
& ADP

12.  Enzyme systems that synthesize prostaglandins, Fibrin
stabilizing factor and growth factor
 Growth factor causes vascular endothelial cells , vascular
smooth muscle cells and fibroblast to multiply and grow , thus
causing cellular growth helps in repair the damaged walls .
 Cell membrane has a coat of glycoprotein , which repulses
the adherence to normal endothelium and causes adhesion to
injured areas
 Phospholipids

13. Contact of platelet to damaged vessels
Begins to swell & assume irregular forms with
numerous irradiating pseudopods
Activation of contractile proteins Release of
granules
Adherence of platelets to collagen in the tissue with
vWF
Secrete large quantities of ADP to form thromboxane A2
,which act on nearby platelets an activate them

14.  Large mutimeric glycoprotein present in blood
plasma , and produced exclusively as extra largre
Vwf in endothelium , megakaryocytes and
subendothelial connective tissue
 The basic Vwf molecule is a 2050 aminoacid
protein molecules
 Functions :
- Binding with other proteins
- Platelet adhesion to wound sites

17.  The clot begins to develop in 15 to 20 seconds if the trauma to
the vascular wall has been severe .
 1 to 2 minutes if the trauma has been minor.
 Activator substances from the traumatized vascular wall, from
platelets, and from blood proteins adhering to the traumatized
vascular wall initiate the clotting process.

18.  Pro coagulants –which promote coagulation
 Anticoagulatants – Which prevents coagulation
 In the blood stream, the anticoagulants normally
predominate, so that the blood does not coagulate
while it is circulating in the blood vessels.
 But when a vessel is ruptured, procoagulants
from the area of tissue damage become “activated”
and override the anticoagulants, and then a clot
does form.

19.  The 3 main steps in clotting are ,
(1) Formation of activated substances, prothrombin
activator
(2) Conversion of prothrombin into thrombin
(3) Conversion of fibrinogen into fibrin

20.  Prothrombin is a plasma protein, an alpha2-globulin, having
a molecular weight of 68,700. It is present in normal plasma in
a concentration of about 15 mg/dl.
 It is an unstable protein that can split easily into smaller
compounds, one of which is thrombin, which has a molecular
weight of 33,700, almost exactly one half that of prothrombin.
 Prothrombin is produced by the liver , Vitamin K is required
by the liver for normal formation of prothrombin as well as for
formation of a few other clotting factors.

21.  CONVERSION OF PROTHROMBIN TO
THROMBIN:
 prothrombin activator is formed as a result of rupture of a
blood vessel or as a result of damage to special substances in
the blood.
Prothrombin
ca+
Thrombin
 The rate-limiting factor in causing blood coagulation is
 usually the formation of prothrombin activator.

22.  Fibrinogen is a high molecular weight protein (MW =
340,000) that occurs in the plasma in quantities of 100 to 700
mg/dl.
 Fibrinogen is formed in the liver, and liver disease can
decrease the concentration.
 Because of its large molecular size, little fibrinogen normally
leaks from the blood vessels into the interstitial fluids, and
because fibrinogen is one of the essential factors in the
coagulation process, interstitial fluids ordinarily do not
coagulate.

23.  It acts on fibrinogen to
remove four low-molecular
weight peptides from each
molecule of fibrinogen,
forming one molecule of
fibrin monomer.
 Automatic capability to
polymerize with other fibrin
monomer molecules to form
fibrin fibers.
 Fibrins at the early stages are
held together by weak non
covalent hydrogen bonds ,
weak clot formation .

24.  Fibrin stabilizing factor :
Present small amounts in normal
plasma globulins ,and is released
by platelets.
 Gets activated by thrombin
 Formation of covalent bonds
 Multiple cross linkages between
adjacent fibrin fibers, thus adding
tremendously to the three-
dimensional strength of the fibrin
meshwork.

25. Blood clot:
 Meshwork of fibrin fibers running in all directions.
 Entrapping blood cells, platelets, and plasma.
 The fibrin fibers also adhere to damaged surfaces of blood
vessels; therefore, the blood clot becomes adherent to any
vascular opening and thereby prevents further blood loss.
 CLOT RETRACTION :
 Within few minutes after clot forms it starts retracting and
expresses most of the fluid from the clot within 20-60 minutes,
the fluid formed is serum , which doesn’t have the clotting
factors.

26.  Clotting initiated mainly by 3 mechanisms:
(1) Trauma to the vascular wall and adjacent tissue
(2) Trauma to the blood
(3) contact of the blood with damaged endothelial cells or with
collagen and other tissue elements outside the blood vessel.
 Each instance it leads to the formation of prothrombin
activator , this is thought to be formed by 2 mechanisms
 (1) By the extrinsic pathway that begins with trauma to the
vascular wall and surrounding tissues
 (2) By the intrinsic pathway that begins in the blood itself.

27.  In both the extrinsic and the intrinsic pathways, a series of
different plasma proteins called blood clotting factors play
major roles.
 Most of these are inactive forms of proteolytic enzymes.
When converted to the active forms, their enzymatic actions
cause the successive, cascading reactions of the clotting
process.

29.  The extrinsic pathway
for initiating the
formation of
prothrombin activator
begins with a
traumatized vascular
wall or traumatized
extravascular tissues
that come in contact
with the blood.

31.  At first, the Factor V in the prothrombin activator complex is
inactive, but once clotting begins and thrombin begins to form,
the proteolytic action of thrombin activates Factor V. This
becomes an additional strong accelerator of prothrombin
activation.
 Thus, in the final prothrombin activator complex, activated
Factor X is the actual protease that causes splitting of
prothrombin to form thrombin.
 Activated Factor V greatly accelerates this protease activity,
and platelet phospholipids act as a vehicle that further
accelerates the process.

32. Blood trauma
Activation of factor XII & release of phospholipids
XIIa
Factor XI activation (HMW kininogen)
Factor IX activation
Factor X activation
factor V
Prothrombin activator

35.  An especially important difference between the
extrinsic and intrinsic pathways is that the extrinsic
pathway can be explosive; once initiated, its speed of
completion to the final clot is limited only by the
amount of tissue factor released from the traumatized
tissues and by the quantities of Factors X, VII, and V in
the blood.
 With severe tissue trauma, clotting can occur in as little
as 15 seconds.
 The intrinsic pathway is much slower to proceed,
usually requiring 1 to 6 minutes to cause clotting.

36. ROLE OF CALCIUM IN THE INTRINSIC AND
EXTRINSIC PATHWAY :
 calcium ions are required for promotion or acceleration of all
the blood-clotting reactions. Therefore, in the absence of
calcium ions, blood clotting by either pathway does not occur.
 In the living body, the calcium ion concentration seldom falls
low enough to significantly affect the kinetics of blood
clotting.
 When blood is removed from a person the clotting can be
prevented by reducing the calcium ion concentration below
threshold level ,either by deionizing the Ca (citrate ion) or by
precipitating the calcium by oxalate ion.

37. (1) Clotting in normal vascular system is prevented
by,
- Smoothness of endothelial cell surface
- Glycocalyx
- Thrombomodulin
- Protein C ( thrombomodulin- thrombin
complex),inactivatingV&VIII
 When the endothelial wall is damaged, its smoothness and its
glycocalyx-thrombomodulin layer are lost, which activates
both Factor XII and the platelets, thus setting off the intrinsic
pathway of clotting. If Factor XII and platelets come in
contact with the subendothelial collagen, the activation is even
more powerful.

38. (2) Antithrombin action of fibrin &
antithrombin III
 Fibrin fibers
 Antithrombin III /Antithrombin- heparin co factor: Alpha
globulin
 While a clot is forming, about 85 to 90 per cent of the
thrombin formed from the prothrombin becomes adsorbed to
the fibrin fibers as they develop.This helps prevent the spread
of thrombin into the remaining blood and, therefore, prevents
excessive spread of clot.
 The thrombin that does not adsorb to the fibrin fibers soon
combines with antithrombin III, which further blocks the
effect of the thrombin on the fibrinogen and then also
inactivates the thrombin itself during the next 12 to 20
minutes.

39. (3) HEPARIN:
 The heparin molecule is a highly negatively charged conjugated
polysaccharide.
 Mainly produced by mast cells(pericapillary connective tissue) &
basophil cells of blood ,mainly near the capillaries of lung & liver
 It has little or no anticoagulant properties, but when it combines
with antithrombin III, the effectiveness of antithrombin III for
removing thrombin increases by a hundredfold to a thousandfold,
and thus it acts as an anticoagulant.
 The complex of heparin and antithrombin III removes several other
activated coagulation factors in addition to thrombin, includes
activated Factors IX, X ,XI , XII .

41.  Plasminogen /profibrinolysin ( plasma protein )
t- PA ( injured tissues & vascular endothelium)
Plasmin /Fibrinolysin ( proteolytic enzyme)
Digests fibrin fibers, fibrinogen , factor II,V, VIII,XII
 Important function of the plasmin system is to remove minute
clots from millions of tiny peripheral vessels that eventually
would become occluded.

42. Vitamin K deficiency
Hemophilia
Thrombocytopenia

43.  Most of the clotting factors are formed by liver –cirrhosis,
hepatitis
 Another reason to depress the formation of clotting factors is
by deficiency of vitamin K
 Vitamin K is necessary for liver formation of five of the
important clotting factors:
 Prothrombin (II)
 Stable factor (VII)
 Antihemphilic factor B (IX)
 Stuart power factor (X)
 Protein C

44.  Vitamin K is continually synthesized in the intestinal tract by
bacteria, so that its deficiency seldom occurs in the normal
person as a result of dietary deficiency .
 vitamin K deficiency often occurs as a result of
- poor absorption of fats from the gastrointestinal tract.
(vitamin K is fat-soluble and ordinarily is absorbed into the
blood along with fat.)
- Failure to secrete bile .

45.  Bleeding disease occurs exclusively in males .
 Due to deficiency or abnormality of factor VIII, known as
classic hemophilia/ hemophilia A (85%)
 Due to deficiency of factor IX (15%)
 Factor VIII Large component
Small component (intrinsic clotting )
- The variable degrees of deficiency in the level of factor VIII
is related to mutation in factor VIII gene.
- Treatment involves infusion of factor VIII

47.  Reduction in number of platelets in circulating blood .
 Bleeding is usually from many small venules or capillaries, rather
than from larger vessels as in hemophilia.
 As a result, small punctate hemorrhages occur throughout all the
body .
 The skin of such a person display many small, purplish blotches,
giving the disease the name thrombocytopenic purpura.
 Most people with thrombocytopenia have the disease known as
idiopathic thrombocytopenia, means thrombocytopenia of unknown
cause.
Specific antibodies have formed and react against the platelets
themselves to destroy them .
Treatment:Fresh whole blood transfusion , splenectomy

49. Vascular defect
Platelet defect
Coagulation defect
Excessive fibrinolysis

51.  THROMBI: Abnormal clot develops in a blood coat.
 EMBOLI : Freely flowing clot
 Causes of Thromboembolic Conditions. :
(1) Any roughened endothelial surface of a
vessel—as may be caused by arteriosclerosis, infection, or
trauma
 (2)Blood often clots when it flows very slowly through blood
vessels, where small quantities of thrombin and other
procoagulants are always being formed.

53.  Disseminated intravascular coagulation
 This often results from the presence of large amounts of
traumatized or dying tissue in the body that releases great
quantities of tissue factor into the blood. Frequently, the clots are
small but numerous, and they plug a large share of the small
peripheral blood vessels.
 Occurs mainly in persons affected with septicemia , in which
either circulating bacteria or bacterial toxins—especially
endotoxins— activate the clotting mechanisms.
 Plugging of small peripheral vessels greatly diminishes delivery
of oxygen and other nutrients to the tissues.

55. Von willebrand’s disease :
 Autosomal dominant trait ,deficiency of von willebrand
factor .
 Spontaneous bleeding of oral mucous membrane, excessive
bleeding from the wounds , menorrhagia
 Prolonged bleeding time , instead of normal platelet count
 Variants are ,
- Type I : reduction in circulating vWF
- Type II : A- Absence of high molecular weight multimers
B- Functionally abnormal high molecular
multimers are formed (chronic thrombocytopenia)
- The patients with VWD have a compound defect involving
platelet function and coagulation pathway .

56. IDIOPATHIC THROMBOCYTOPENIC PURPURA :
 Disorder of autoimmune origin
 An acute , self limited form that follows viral infections has
been described in children .
 Females ( 20-40 yrs )
 Occur in association with SLE , Lymphoma , Collagen
vascular diseases
 Pathogenesis:
1 . Antiplatelet Ig directed against platelet membrane
glycoprotein ( Gb IIb /IIIa)
2. Binding of auto antibodies to megakaryocyte .
- Histologically marrow may appear normal ,but reveals
increased number of megakaryocytes ,with single nucleus .

57. Glanzmann’s thrombosthenia:
 Autosomal recessive disorder
 Rare platelet function disorder ,caused by abnormality in the genes for
glycoprotein II b / III a , a fibrinogen receptor .
 Symptoms:
- Easy bruising
- Nasal bleeding
- Bleeding from gums
- Increased menstrual bleeding
- Post operative bleeding
 Treatment :
Antifibrinolytic drugs
Recombinant factor VIIa
Fibrin sealants
Hormonal contraceptives (to control excessive menstrual bleeding)
Iron replacement (if necessary to treat anemia caused by excessive
or prolonged bleeding)
-Platelet transfusions (only if bleeding is severe)

58.  BERNARD SOULIER SYNDROME :
 Also known as hemorrhagiparous thrombocytic dystrophy
 Autosomal recessive coagulopathy
 Caused by deficiency of glycoprotein Ib (Gb Ib), a receptor
for vWF ,important glycoprotein involved in hemostasis.
 Giant platelet disorder
 Signs & symptoms:
Pre operative &post operative bleeding
Bleeding gums
Easy bruising ,epistaxis
Abnormally prolonged bleeding from injuries
 Diagnosis: Prolonged bleeding time , increased
megakaryocytes, thrombocytopenia ,enlarged platelets .

59. WISKOTT- ALDRICH SYNDROME :
Caused by mutation in WAS gene , more common in males
Reduced ability to form blood clots.
Microthrombocytopenia.
This platelet abnormality ,which is typically present from birth
can lead to easy bruising or episodes of prolonged bleeding .
Eczema ,increased susceptibility to infections
Greater risk of developing auto immune disorder.

60.  Primary & secondary hemostasis
 Disorders of primary hemostasis:
- Integrity of vascular wall & adequacy of platelets are
essential for primary hemostasis .
-failure of this system may lead to disorders of primary
hemostasis . Includes ,
- Thrombocytopenia
- Platelet functional disorder
- Purpura
- Echymosis

61.  Disorders of secondary hemostasis :
( Disorders of fibrin clot formation )
- The deficiencies of coagulation factors involved in the
intrinsic and extrinsic pathways are the common causes of
inadequate fibrin clot formation
- Congenital and acquired deficiencies of these factors lead to
secondary hemostasis.
- Liver diseases
- DIC
- Vitamin K deficiency

62. ANTICOAGULANTS
 COUMARINS /WARFARINS:
 Fall in the plasma levels of prothrombin and Factors VII, IX,
and X, indicating that warfarin has a potent depressant effect
on liver formation of these compounds .
 Warfarin causes this effect by blocking the action of vitamin
K, it takes atleast 48-72 hours for the anticoagulant effect to
happen .Monitored by PT times .
 After administration of an effective dose of warfarin, the
coagulant activity of the blood decreases to about 50 per cent
of normal by the end of 12 hours and to about 20 per cent of
normal by the end of 24 hours.

64.  To summarize, hemostasis is the cessation of
bleeding from a cut or severed vessel , the
diagnosis of bleeding disorders is very essential in
clinical practice & is based upon the clear
understanding of the mechanisms of primary and
secondary hemostasis .

65.  Gyton & Hall ,Text book of medical
physiology ; 11th edition.
 Christopher L. B Lavelle , Applied oral
physiology; 2nd edition.
 Kumar , Cotran ,Robbins, Basic patholgy ;
7th edition
 Praful B . Godkar ,Darshan
P.Godkar,Textbook Of Medical Laboratory
Technology ; 2nd edition .
 www. Genetic home references.com